Redesigned for 2012, Audi's A6 lineup is halfway back to full strength with the introduction of the Avant station wagon. The high-powered S6 and RS6 versions still are waiting in the wings—as is a hybrid model designed mostly with our market in mind, even if U.S. availability is as-yet unconfirmed—but already this is an impressive family of vehicles. In Europe, though, where a diesel-powered station wagon is the stereotypical executive car, the Avant is the most critical of all A6s.

Audi just made the executive-wagon segment a lot more interesting, with a twin-turbocharged variation of its 3.0-liter TDI turning out 313 hp and an even more impressive 479 lb-ft of torque. Not only is it a powerful mill, but this diesel has attitude. Many oil-burners are impressive in their power delivery and massive torque, but lack soul. The 3.0-liter TDI, on the other hand, fires up with an impressive growl, and the sound gets better as you push it through the gears. Its voice is reminiscent of an old-fashioned V-8’s, a sound that is clearly audible inside and out. Think we’re crazy? Just wait until you hear how Audi did it: The company stuffed an extremely durable speaker into the exhaust system that allows it to alter the engine note. It can even be adjusted on the move.

Going Right to Ludicrous Speed

Driving the A6 Avant is even better than listening to it. The all-wheel-drive chassis copes well with the TDI's grunt. The rear differential distributes the power for maximum agility, and it takes a heavy misstep to throw the Avant off course. The car should need just 5.5 seconds to accelerate from 0 to 60 mph. Top speed is a governed 155 mph, a speed the Avant reaches with ease. On unlimited stretches of autobahn, the twin-turbo TDI’s sheer grunt at velocities of 130 mph and above is remarkable.

Its torque is so massive that it surpassed the capacity of Audi’s seven-speed dual-clutch transmission and the company had to install an eight-speed torque-converter automatic from ZF. There are three other diesel options in this car—a 177-hp 2.0-liter four and two single-turbo versions of the 3.0-liter V-6 making 204 and 245 hp—but the twin-turbo V-6 is clearly the bad boy of the lineup. Even the most powerful gasoline engine Audi offers, the familiar supercharged 3.0-liter V-6, lacks the brute force of the top TDI. Better yet, the beastly diesel returns 37 mpg on the (hopelessly optimistic) European combined cycle.

Stylistically, the Avant conversion works well on the A6, but it doesn't transform a conservative sedan design into a head-turner. While the previous-generation A6 Avant sported a markedly different rear end, this Avant looks almost identical to the sedan except for the elongated roofline. Even the overbite of the taillights remains. Additionally, the A6 Avant offers virtually all of the sedan's technological features, including a roster of assistance systems that borders on ridiculous, plus WiFi and Google-based telematics, as well as countless options for personalization.

Let Me Get That For You. And That. And That

Of course, the biggest difference between the sedan and the Avant is cargo capacity. There are a lot of practical options, such as a power cargo cover and a power hatch that opens when you wave your foot below the rear bumper—the latter particularly convenient when you have your hands full of groceries and don't want to reach for the trunk latch.

The A6 Avant’s success in Europe is almost assured, but the car is very unlikely to come to the U.S. Audi would like its dealers to instead focus on the A6 sedan and the Q5. Unless station wagons in general experience a sudden and unexpected rebound here, we won't be seeing the Avant on our lots. And while Audi is planning to offer the A6 sedan here with a diesel V-6, it will most likely be a front-wheel-drive single-turbo version with something closer to 250 hp. Pity.